How to setup a Battery System


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1. Choose your battery

Using the Burnsco Battery Chart find your battery size and match it with a Battery Box.  If unsure, speak with a Burnsco staff member.

Decide on a location for the battery. Ideally a place that won’t get a lot of salt water, usually high up in the middle section of the stern of your boat. 

Decide on the location for the Battery (isolator) Switch.  Usually it is on the starboard side under the gunnels.

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Products you will need

2. Installing the battery

Place your Battery and Battery Switch in their desired locations. 
Drill holes to fasten down the battery straps which will hold the battery and battery box in place. 

TIP Use Duralac on stainless screws to avoid electrolysis with the aluminum. 

Why Secure the Battery?
It is very important to secure your battery, ideally in a battery box. Spilt battery acid or an electrical short caused by a dislodged battery in rough seas can have disastrous consequences. 

3. Wiring the battery

Choose the size of Marine Cable. Red for positive and black for negative.

TIP The larger cable you use allows for more capacity later on, e.g. if you want to wire up an anchor winch.  A common size is 10-25mm.

Why Marine Cable?
Marine cable is tinned copper which gives maximum protection against corrosion. Standard copper wire will corrode and blacken over time in a salt water environment. 

Measure the 3 lengths of marine cable you will need for:

1. the positive wire from battery to battery switch.

2. the positive wire from battery switch to positive terminal of the busbar by the switch panel.

3. the negative wire from battery to negative terminal of the busbar.

Diagram 1.

TIP When measuring, allow for an extra run of the cable so you can tuck the cable up and out of way and go around corners. 

4. Preparation of wires

You will need to attach Cable Lugs and apply Heat Shrink to the wires.

Why Heatshrink?
It is important to seal the ends of all electrical cable in a marine environment, using heatshrink and/or a sealant. Water can be sucked into cable with capillary motion, or wicking. Wicking is the ability of a liquid to flow into narrow spaces without the assistance of, or even in opposition to, external forces like gravity. 

1. Cut the wire using Cable Cutter or Craft Knife and expose 10mm of bare wire.

2. Use Crimpers to crimp Cable Lugs onto bare wire.

3. Cut 30mm of heat shrink, slide heat shrink over the cable lug and use heat gun to melt heat shrink into place. 

4. Repeat this process for both ends of each cable run using black heat shrink for negative and red heat shrink for positive wires.

5. Wire up the battery switch

Connect the two positive wires onto the battery switch.  The first runs from the battery to the battery switch.  The second runs for the battery switch to the positive busbar.

Diagram 2.

Fasten battery switch with 4 screws to a suitable dry secure location.

SAFETY TIP When you’re working on a 12V system, it’s important not to let the positive and negative wires touch as this will arc the battery and give you shock. Tape up the positive terminal or the exposed wires to help prevent this.

Run your negative wire up the length of boat to the negative Busbar. You should now be left with just the positive and negative wires down the back ready to be attached to the battery. 

You may like to put an Inline Fuse (minimum of 30A) in the positive wire between the battery and the battery switch.

Make sure the battery switch is off.  Then connect the negative wire to the battery first. When this is secured, connect the positive. Tighten up and you are nearly done.

5. Finishing up

When all your wiring is connected use Cable Ties to tie them out of the way.

Why Secure the Cables?
The vibrations and movement in a boat can cause cables to move and chaff, ultimately causing electrical shorts or failure. All cables should be well secured with clips and/or cable ties and positioned where they cannot be damaged by other equipment or people when moving about.  

Double check all bolts and battery connections are snug and tight.
Sometimes it is beneficial to use Nyloc Nuts to stop them vibrating loose.

Finally, spray some CRC Soft Seal evenly over the terminals. Use a cloth or Masking Tape to protect other items from the spray. The Soft Seal will seal the connections and prevent corrosion which could cause shorting.